[libvirt] [PATCH 34/26] snapshot: add <disks> to snapshot xml

[Eric Blake]

On 08/19/2011 07:29 PM, Eric Blake wrote:
> On 08/19/2011 03:58 PM, Eric Blake wrote:
>> Adds an optional element to<domainsnapshot>, which will be used
>> to give user control over external snapshot filenames on input,
>> and specify generated filenames on output.
>>

One more thing to squash in - make the auto-generation of names not 
provided by the user be consistent across hypervisors, by stripping any 
suffix after the last '.' and replacing it with the name of the snapshot.

diff --git i/docs/formatsnapshot.html.in w/docs/formatsnapshot.html.in
index e476c8f..e1a43e7 100644
--- i/docs/formatsnapshot.html.in
+++ w/docs/formatsnapshot.html.in
@@ -129,7 +129,10 @@
              optional sub-element <code>driver</code>, with an
              attribute <code>type</code> giving the driver type (such
              as qcow2), of the new file created by the external
-            snapshot of the new file.  Remember that with external
+            snapshot of the new file.  If <code>source</code> is not
+            given, a file name is generated that consists of the
+            existing file name with anything after the trailing dot
+            replaced by the snapshot name.  Remember that with external
              snapshots, the original file name becomes the read-only
              snapshot, and the new file name contains the read-write
              delta of all disk changes since the snapshot.
diff --git i/src/conf/domain_conf.c w/src/conf/domain_conf.c
index e1f71a6..c9daebb 100644
--- i/src/conf/domain_conf.c
+++ w/src/conf/domain_conf.c
@@ -11347,6 +11347,43 @@ 
virDomainSnapshotAlignDisks(virDomainSnapshotDefPtr def,

      qsort(&def->disks[0], def->ndisks, sizeof(def->disks[0]), disksorter);

+    /* Generate any default external file names.  */
+    for (i = 0; i < def->ndisks; i++) {
+        virDomainSnapshotDiskDefPtr disk = &def->disks[i];
+
+        if (disk->snapshot == VIR_DOMAIN_DISK_SNAPSHOT_EXTERNAL &&
+            !disk->file) {
+            const char *original = def->dom->disks[i]->src;
+            const char *tmp;
+
+            if (!original) {
+                virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                     _("cannot generate external backup 
name "
+                                       "for disk '%s' without source"),
+                                     disk->name);
+                goto cleanup;
+            }
+            tmp = strrchr(original, '.');
+            if (!tmp || strchr(tmp, '/')) {
+                ignore_value(virAsprintf(&disk->file, "%s.%s",
+                                         original, def->name));
+            } else {
+                if ((tmp - original) > INT_MAX) {
+                    virDomainReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                                         _("integer overflow"));
+                    goto cleanup;
+                }
+                ignore_value(virAsprintf(&disk->file, "%*s%s",
+                                         (int) (tmp - original), original,
+                                         def->name));
+            }
+            if (!disk->file) {
+                virReportOOMError();
+                goto cleanup;
+            }
+        }
+    }
+
      ret = 0;

  cleanup:

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org